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Subject: Re: [PATCH v8 18/18] KVM: SVM: Enable SEV live migration feature
 implicitly on Incoming VM(s).
To:     Ashish Kalra <ashish.kalra@amd.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
        joro@8bytes.org, bp@suse.de, Thomas.Lendacky@amd.com,
        x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        srutherford@google.com, rientjes@google.com,
        venu.busireddy@oracle.com, brijesh.singh@amd.com
References: <cover.1588711355.git.ashish.kalra@amd.com>
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 <7a3e57c5-8a8c-30dc-4414-cd46b201eed3@redhat.com>
 <20201204214656.GC1424@ashkalra_ubuntu_server>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <17551007-bcc9-e772-5318-264287ee8ae9@redhat.com>
Date:   Sun, 6 Dec 2020 11:18:20 +0100
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On 04/12/20 22:46, Ashish Kalra wrote:
>> I would prefer that userspace does this using KVM_SET_MSR instead.
>
> Ok.
> 
> But, this is for a VM which has already been migrated based on feature
> support on host and guest and host negotation and enablement of the live
> migration support, so i am assuming that a VM which has already been
> migrated can have this support enabled implicitly for further migration.

It's just that it is a unexpected side effect of 
KVM_SET_PAGE_ENC_BITMAP.  I prefer to have it tied to the more obvious 
KVM_SET_MSR ioctl.

Paolo